Method of Generating a Buffer Status for a Wireless Communication System and Related Device

1. A method of generating a buffer status of a packet data convergence protocol, hereinafter called PDCP, layer for a user equipment in a wireless communication system, the method comprising: including volume information of packets, which have been submitted to a radio link control, hereinafter called RLC, layer and have not been confirmed by the RLC layer due to buffer clearing of the RLC layer of the user equipment, or have not been confirmed by a PDCP status report, in a buffer status report defined as a MAC (Medium Access Control) control element wherein a buffer size field in the Buffer Status Report MAC Control Element identifies the total amount of data available across all logical channels of a logical channel group after a MAC PDU has been built; wherein the buffer clearing of the RLC layer of the user equipment is caused by a re-establishment of the RLC layer or a radio resource control (RRC) connection re-establishment.

2. The method of claim 1 , wherein the packets are service data units, hereinafter called SDUs.

3. The method of claim 1 , wherein the packets are protocol data units, hereinafter called PDUs.

4. The method of claim 1 , further comprising including volume information of packets, which have not been submitted to the RLC, in the buffer status report.

5. The method of claim 4 , wherein the packets, which have not been submitted to the RLC layer, comprises SDUs, which have not yet been processed by the PDCP layer, or control or data PDUs whose SDUs have been processed by the PDCP layer.

6. The method of claim 1 , wherein the packets belong to a PDCP entity of the PDCP layer.

7. The method of claim 1 , wherein the buffer status report is a regular buffer status report, a periodic buffer status report, or a padding buffer status report.

8. A communication device of a wireless communication system for accurately generating a buffer status of a packet data convergence protocol, hereinafter called PDCP, layer, the communication device comprising: a processor for processing storage data; a communication interfacing unit for exchanging signals with a peer communication device of the wireless communication system; a control unit coupled to the processor and communication interfacing unit, for controlling the communication interfacing unit and the communication device according to processing results of the processor; and a computer readable recording medium coupled to the processor, for storing the storage data; wherein the storage data comprises: program code for including volume information of packets, which have been submitted to a radio link control, hereinafter called RLC, layer and have not been confirmed by the RLC layer due to buffer clearing of the RLC layer of a user equipment, or have not been confirmed by a PDCP status report, in a buffer status report defined as a MAC (Medium Access Control) control element wherein a buffer size field in the Buffer Status Report MAC Control Element identifies the total amount of data available across all logical channels of a logical channel group after a MAC PDU has been built; wherein the buffer clearing of the RLC layer of the user equipment is caused by a re-establishment of the RLC layer or a radio resource control (RRC) connection re-establishment.

9. The communication device of claim 8 , wherein the packets are service data units, hereinafter called SDUs.

10. The communication device of claim 8 , wherein the packets are protocol data units, hereinafter called PDUs.

11. The communication device of claim 8 , further comprising including volume information of packets, which have not been submitted to the RLC layer in the buffer status report.

12. The communication device of claim 11 , wherein the packets, which have not been submitted to the RLC layer comprises SDUs, which have not yet been processed by the PDCP layer, or control or data PDUs whose SDUs have been processed by the PDCP layer.

13. The communication device of claim 8 , wherein the packets belong to a PDCP entity of the PDCP layer.

14. The communication device of claim 8 , wherein the buffer status report is a regular buffer status report, a periodic buffer status report, or a padding buffer status report.